Abstract 17035: Inhibition of DNMT and HDAC6 Together Regulates Macrophage Polarization by FoxO1-HIF2α Signaling and Protects Endotoxemia-Induced Inflammation

Abstract

Introduction: Acute lung injury (ALI) is a common pulmonary disease caused by bacterial infection leading to an imbalance between pro-inflammatory and anti-inflammatory immune responses. Studies have shown that macrophage polarization (M1 and M2) during ALI plays a key role in regulating these responses. Hypothesis: We hypothesized that combined treatment with 5-Aza 2-deoxycytidine (Aza) + tubastatin A (TBA) would reduce inflammation and promote an anti-inflammatory M2 macrophage phenotype by regulating the HIF2α signaling pathway. Methods: To show the effect of Aza+TBA, lipopolysaccharide (LPS)-induced macrophages (RAW 264.7) were treated with either Aza (50nM), TBA n(750nM), or together (Aza+TBA) for 24 hours. The mRNA and protein expressions of FoxO1, HIF2α, NOS2 (M1), and CD206 (M2) were measured by qRT-PCR and Western analyses in lung tissue and macrophages. Results: Our results revealed that LPS induced macrophages showed an increased expression of NOS2 (M1) and decreased expression of Fizz-1 (M2) whereas the LPS-induced macrophages were treated with Aza+TBA showed decreased NOS2 (Fig. A) and increased Fizz-1 mRNA (Fig. B) and protein expressions. Furthermore, the LPS significantly decreased the mRNA and protein expressions of FoxO1 and HIF2α in macrophages. These expressions were significantly increased when the LPS-induced macrophages were treated with Aza +TBA (Fig. C) . These results suggest that Aza+TBA treatment together generates more M2 macrophages there by reducing the LPS-induced inflammatory responses. Conclusions: Overall, these data show the first time that the combinatorial treatment with Aza+TBA regulates macrophage cell polarization and abrogates LPS-induced inflammation through FoxO1-HIF2α signaling pathway. Thus, epigenetic modifiers may be potential therapeutic drugs for ALI. <!--EndFragment-->